feat(datepicker) New input pickerInitialDate

- New input (optional) that sets the intial date to display (null = today)
- Updated demo page

Partially addresses edcarroll#165

demo/src/app/pages/modules/datepicker/datepicker.page.ts

@@ -94,6 +94,11 @@ export class DatepickerPage {
                                  "<code>date</code>, <code>time</code>, <code>month</code> & <code>year</code>.",
                     defaultValue: "datetime"
                 },
+                {
+                    name: "pickerInitialDate",
+                    type: "Date",
+                    description: "Sets the intial date to display (null = today)."
+                },
                 {
                     name: "pickerMaxDate",
                     type: "Date",

src/modules/datepicker/directives/datepicker.directive.ts

@@ -1,7 +1,6 @@
-
 import {
     Directive, ElementRef, Renderer2, EventEmitter, Output, Input,
-    HostListener, OnChanges, SimpleChanges
+    HostListener, OnChanges, SimpleChanges, OnInit
 } from "@angular/core";
 import { AbstractControl, ValidationErrors } from "@angular/forms";
 import {
@@ -12,14 +11,15 @@ import { IDatepickerLocaleValues, RecursivePartial, SuiLocalizationService } fro
 import { SuiPopupComponentController, PopupAfterOpen, PopupConfig, PopupTrigger } from "../../popup";
 import { SuiDatepicker, DatepickerMode } from "../components/datepicker";
 import { CalendarConfig, YearConfig, MonthConfig, DatetimeConfig, TimeConfig, DateConfig } from "../classes/calendar-config";
+import { isValid } from "date-fns";
 
 @Directive({
     selector: "[suiDatepicker]",
     providers: [customValidatorFactory(SuiDatepickerDirective)]
 })
 export class SuiDatepickerDirective
        extends SuiPopupComponentController<SuiDatepicker>
-       implements ICustomValueAccessorHost<Date>, ICustomValidatorHost, OnChanges, PopupAfterOpen {
+       implements ICustomValueAccessorHost<Date>, ICustomValidatorHost, OnChanges, PopupAfterOpen, OnInit {
 
     private _selectedDate?:Date;
 
@@ -63,6 +63,9 @@ export class SuiDatepickerDirective
         this.writeValue(this.selectedDate);
     }
 
+    @Input("pickerInitialDate")
+    public initialDate?:Date;
+
     @Input("pickerMaxDate")
     public maxDate?:Date;
 
@@ -148,6 +151,18 @@ export class SuiDatepickerDirective
         }
     }
 
+    public ngOnInit():void {
+        if (this.initialDate !== undefined) {
+            // Need to explicitly check for null
+            // tslint:disable-next-line:no-null-keyword
+            if(this.initialDate !== null) {
+                this._selectedDate = isValid(this.initialDate) ? new Date(this.initialDate) : undefined;
+            } else {
+                this._selectedDate = new Date();
+            }
+        }
+    }
+
     public ngOnChanges({ maxDate, minDate, mode }:SimpleChanges):void {
         if (maxDate || minDate || mode) {
             this.onValidatorChange.emit();